The Douglas County Sheriff's Office tells 9NEWS a 37-year-old woman was killed around 3:30 p.m. Her name has not been released.

Radar shows there was one strike near Sedalia, and three strikes near Roxborough on Sunday afternoon.
(Photo: 9NEWS Weather Center)

A 15-year-old girl was also seriously injured and taken to the hospital. South Metro says this girl, a family friend, was also riding a horse. A third rider, who turned out to be the mother of the 37-year-old, was far enough away at the time and uninjured.

The three saw the storms, and were looking for a place to meet up.

1 of 2 - SMFR assisted West Douglas with a tragic scene on Rainbow Creek Rd this afternoon. Lightning killed 1 adult female and her horse.